1. Field of the Invention
The present invention relates to a vehicle steering apparatus.
2. Description of Related Arts
As a vehicle steering apparatus, an electric power steering apparatus is known which comprises a torque sensor for detecting steering torque inputted into a steering member, and an electric motor for generating power on the basis of the abovementioned steering torque.
For example, in Document 1 (Japanese Unexamined Patent Publication No. 2006-46376), an electric power steering apparatus is disclosed which comprises an electric motor and a speed reduction mechanism for amplifying the output of the electric motor and transmitting the same to a steering shaft. A part of the speed reduction mechanism is provided coaxially with the steering shaft and the electric motor is disposed around the speed reduction mechanism.
Further, in Document 2 (Japanese Unexamined Patent Publication No. 2005-145436), an electric power steering apparatus is disclosed which comprises an electric motor provided coaxially with a steering shaft. In this apparatus, the output of the electric motor is directly transmitted to the steering shaft, and a torque sensor is disposed coaxially with the steering shaft outside a frame of the electric motor.
The electric power steering apparatus disclosed in the Document 2 has an advantage that, by omitting a speed reduction mechanism, the apparatus can be reduced in size in the radial direction of the steering shaft.
However, by omitting a speed reduction mechanism, a high-power-output and large-sized electric motor is necessary. As a result, the electric power steering apparatus has a disadvantage that the apparatus grows in size in the axial direction of the steering shaft.
An object of the present invention is to provide a vehicle steering apparatus reduced in size in the radial and the axial directions of the steering shaft.